#pragma once

#include <pthread.h>
#include <semaphore.h>
#include <vector>

template <typename T>
class RingQueue
{
private:
    void P(sem_t &sem) { sem_wait(&sem); }
    void V(sem_t &sem) { sem_post(&sem); }
    void Lock(pthread_mutex_t &mutex) { pthread_mutex_lock(&mutex); }
    void Unlock(pthread_mutex_t &mutex) { pthread_mutex_unlock(&mutex); }

public:
    RingQueue(int cap)
        : _ring_queue(cap), _cap(cap), _productor_step(0), _consumer_step(0)
    {
        sem_init(&_room_sem, 0, _cap);
        sem_init(&_data_sem, 0, 0);

        pthread_mutex_init(&_productor_mutex, nullptr);
        pthread_mutex_init(&_consumer_mutex, nullptr);
    }

    void Enqueue(const T &in) // 生产者
    {
        P(_room_sem);
        Lock(_productor_mutex);
        _ring_queue[_productor_step++] = in;
        _productor_step %= _cap;
        Unlock(_productor_mutex);
        V(_data_sem);
    }

    void Pop(T *out)
    {
        P(_data_sem);
        Lock(_consumer_mutex);
        *out = _ring_queue[_consumer_step++];
        _consumer_step %= _cap;
        Unlock(_consumer_mutex);
        V(_room_sem);
    }

    ~RingQueue()
    {
        sem_destroy(&_room_sem);
        sem_destroy(&_data_sem);

        pthread_mutex_destroy(&_productor_mutex);
        pthread_mutex_destroy(&_consumer_mutex);
    }

private:
    std::vector<T> _ring_queue;
    int _cap; // 容量上限

    int _productor_step;
    int _consumer_step;

    sem_t _room_sem;
    sem_t _data_sem;

    pthread_mutex_t _productor_mutex;
    pthread_mutex_t _consumer_mutex;
};